Millions of individuals encounter irregular heartbeats, known as arrhythmias, at some stage in their lives. These are typically harmless and can occur in healthy individuals without heart disease. However, certain abnormal heart rhythms can pose serious health risks, even life-threatening ones. Additionally, the presence of other heart conditions can significantly increase the likelihood of experiencing an arrhythmia.
Disease Categories
Heart disease can be separated into three categories: Electrical, Circulatory and Structural abnormalities.
Electrical: Arrhythmias arise from malfunctions within the heart's electrical system, which is responsible for maintaining a consistent heartbeat. This can manifest as an excessively fast or slow heart rate, or even a chaotic and irregular rhythm. Some arrhythmias pose a serious threat, potentially leading to sudden cardiac death, while others may be harmless albeit bothersome and not life-threatening.
Circulatory: Coronary artery disease, characterized by blockages in the heart's arteries, and high blood pressure are primary contributors to blood vessel disorders. These disorders can have severe consequences, including heart attacks and strokes. Thankfully, a wide range of treatment options are available to manage these conditions.
Structural: Congenital abnormalities (birth defects) and heart muscle disease (cardiomyopathy) are two conditions that can cause damage to the heart muscle or valves.
Electrical Disorders
Arrhythmias that start in the atria, the heart’s upper chambers include:
Atrial Fibrillation (AFib)
Atrial Fibrillation (AFib) is a common heart rhythm disorder affecting over 2 million people in the US and 200,000 in Canada. In AFib, the heart beats irregularly and rapidly due to chaotic electrical signals. The atria, the upper chambers of the heart, can beat up to 300 times per minute, significantly faster than normal.
While not immediately life-threatening, AFib can increase the risk of other heart rhythm problems, lead to persistent fatigue, and even contribute to heart failure, characterized by symptoms like swelling in extremities, fluid buildup, and shortness of breath. Individuals with AFib are at a significantly higher risk of stroke, with a five-fold increased likelihood. Consequently, doctors often prescribe blood thinners (anticoagulants) to reduce this stroke risk.
Infrequent or asymptomatic AFib can be effectively detected using holter monitors. These devices automatically record the heart rhythm when an irregular pattern is detected, allowing for subsequent review by a cardiologist. For persistent AFib, a Holter monitor is typically recommended to confirm adequate heart rate control.
Atrial Flutter
Atrial Flutter shares similarities with Atrial Fibrillation (AFib) in that both conditions cause a rapid heartbeat within the atria. However, unlike AFib, Atrial Flutter is triggered by a single, rapidly circulating electrical wave within the atria. This wave can circulate at extremely high speeds, sometimes reaching up to 300 times per minute, resulting in a very fast heart rate.
Sick Sinus Syndrome
Sick Sinus Syndrome (SSS) is not a specific disease but rather a collection of symptoms indicating dysfunction of the heart's natural pacemaker, the sinus node. In SSS, the heart rate can fluctuate erratically, switching between excessively fast (tachycardia) and excessively slow (bradycardia) rhythms. Treatment for SSS typically involves a combination of medication and an artificial pacemaker.
Sinus Tachycardia
Sinus tachycardia is a normal physiological response where the heart rate increases above the typical resting rate. It's often triggered by factors like excitement, exercise, or fever. Generally, no treatment is necessary as it usually resolves on its own once the triggering factor subsides.
However, if sinus tachycardia occurs at rest or is persistent, it could indicate an underlying medical condition such as hyperthyroidism (overactive thyroid) or anemia (low red blood cell count). In such cases, addressing the underlying cause is crucial.